Method of surface finishing articles



June 8, 1965 P. P. RUPPE 3,187,473

METHOD OF SURFACE FINISHING ARTICLES Filed Nov. 16, 1959 3 Sheets-Sheet1 IN V EN TOR.

Fifi/9 r RUFF! El (fan 5 PM June 8 p p RUPPE METHOD OF SURFACE FINISHINGARTICLES 3 Sheets-Sheet 2 Filed Nov. 16, 1959 HVVENTDR.

BY PA'TIR P. Ra /=5 60,23 a PM A TTOR/VEKS June 8 1965 P. P. RUPPE3,187,473

METHOD OF SURFACE FINISHING ARTICLES Filed Nos 16, 1959 s Sheets-Sheet sINVEN TOR.

PTR map/ 5 swim a. PM

This invention pertains to the artof metal finishing.

More particularly, it relates to Ways and means for surface finishingarticles as by deburring, scrubbing, abradmg, or

the like.

In fabricating metallic parts'and the like, it frequently happensthatburrs and rough surfaces are formed on the articles. One procedurefor removing burrs and roughness of the surfaces of the articles is bybarrel finishing. This procedure involves a barrel and abrasiveparticles inside of the barrel. The articles to be surface finished areplaced in the barrel and the barrel is rotated on its axis whereby bothabrasive particles and articles are tumbled together.

' This procedure cannot be used, however, on many articles because oftheir fragile nature. The tumbling ac tion involved is inherently toorough and hard on such articles. it -In other instances such a procedureis not too effective or at least to have any eflieot on burrs on edgessomewhat shielded from the abrasive particles under tumbling conditions.

United States Patent 3,187,473 Patented June 8, 1965 Still anothermethod concept involved in this invention abrasive'particlesandreturning the abrasive particlesto the-bed. a 1 i These and otherconcepts involved in this invention are present inthe embodimentillustrated inthe drawings which form a material part of the disclosure.

Turning to the'drawings, it will be observed that: a FIG. 1 is a generalside view of-a p'referredenrbodiment of the articledinishing machine ofthis invention;

FIG. 2 is a'plan view of the machine shown'in' BIG. 1; FIG. 3 is anenlarged, partially sectioned, side view of the main portion of theapparatus'of FIG. 1, "which view convey-or means structure I FIG.J4 isan end view ofthe apparatus taken in the direction of arrow 4 inFIG.1.'-

In greater detail, the drawings disclose an article-finish- 7 ingmachine 10. As shown in FIGS. 1 and 2, the machine 10 comprises anarticle feed section 1.1, a bin section 12, a screen section 13, and anabrasive particle return sectionl'.

The article feed section 11 comprises a hopper16 for.

receiving'and storingarticles to be finished; Below the 'discharge'endof the hopper 16 there is provided a vibratory conveyor 17 fordelivering articles from'the hop- In both cases it has been necessary tomanually deburr' each individual article. This, of course, isinefiicient and expensive. There is a need, therefore, for Ways andmeans for mechanically deburrin-g and surface finishing articles of afragile nature and of odd shape.

An object of this invention is to provide ways and means formechanically deburring or surface finishing articles regardless of theirfragility and regardless of any irregularity-in shape. I

A specific object of this invention is to provide a method for surfacefinishing articles, which involves gentle action.

Another specificobject of this invention is to provide a method forsurface finishing articles which, under'barrel finishing procedures,would remain relatively unaffected.

These and other objects which may appear asthis specification proceedsare achieved by this invention.

The method is based on the general concept of forming a bed of particleswhich are abrasive relative to thearticles to be finished, placingarticles to be finished in said bed and establishing and maintainingsaid particles in motion relative to the articles to be finished. I Inaddition to this general. concept, this invention involves the furtherconcept of gently turning over articles in said bed so that all edgesthereof are exposed to abrasive particles moving relative thereto. MAspecific concept relied upon in the method of this in vention is that ofestablishing and maintaining relative motion between abrasive particlesand articles to be finished by subjecting said bed and articles thereinto vibratory conveying forces. In this concept it is necessary that theaverage mass of the abrasive particles-diner from the average mass ofthe articles to be finished. Another specific concept involved in themethod of this invention is that of the vibratory'oonvey-ing forcesbeing applied to cause particles and articles in said bed perj16 to thefront end of the bin section 12. The conveyor"17' includes a' trough orthe like 17a disposed beneath the discharge 'end of the hopper 16inarticlereceiving relation therewith. The trough i's supported onflexible leaves 17b which are mounted in angularly upstanding relationon a support 170. Means, not shown,

coupled to the trough, serve to impart a horizontal reciprocatorycomponent of motion thereto. "However,

' because of the angular disposition of leaves 17b the to generallytravel in one direction and in the path of v 7 travel of said particlesand articles providing a deflector turned over.

trough also has a vertical component of rhotionwith the resultanfmotionbeingalong an inclined plane whose lower end is below the discharge endor hopper 1d and whose upper end is above the bin sectiorilZ." Thereciprocatory orvibratory motion thus'iinparted serves toconvey'articles alongthe trough from beneath the hopper16 to thedischarge end'of trough 17a. This vibratory-conveying principle is wellunderstood in theconveying art and need not be further described.

The bin section 12 comprises a bin zusupported on a vibratory conveyorassembly 21. f The bin 20has a generally horizontally disposed bottom22, a front end wall 23, a pair of side walls' 2.4 and 25 and an endclosure member 26 adjacent the back end thereof. The end closure member26 isan arcuate member 26a preferably semi-circular in"side'view. "It

extends across the width of the bin 20 between the side walls 24 and'25with the concave side thereoffacing the front end wall 23. 'It has'agenerally horizontal and transverse axis of rotation and is pivotallyniounted on said axis to'the side walls 24 and25. Normally, the bottomend of the end closure member 26fbea1rs against the bottom 22 of thebin20. However; by'meansof a crank arm'assembly 27, the 'end closuremember 26 can be pivoted so as to lift its bottom end outof enga'gementwith the bottom "22'and to a sufiicient height to permit finishedarticles and abrasive particles inthe bin to be conveyed'to the screensection'13; To each end of arcuate member 26 are secured ovular endplates 26b and 26c as shown in FIGS. land 3. Theseend plates overlie theinner wallsurface s of bin side walls 24 and 25. Each ovular end platehas a stub shaft as at 26d and 26a which extend through 'holes inthe'bin side walls 24 and 25 and rotatably support the end closure asaforesaid. Stub shaft 262 is secured as by J9 welding, exteriorly of binwall 24 to the crank arm 27a of the crank assembly 27.

The crank assembly 27 may be actuated in any suitable fashion, notshown. For example, manually, by grasping and lifting portion 27b toopen the end closure, and upon release the weight of portion 27b willcause closure of the member 26a. Or, the assembly may be automaticallycontrolled by a suitable electrically, mechanically, or fluid pressureoperated device 270.

The vibratory conveyor assembly 21 for the bin is shown in FIG. 3. It,with the bottom 22, forms a vibratory conveyor bed. It involves a pairof leaf-spring supports 29 and 33 secured by brackets 31 to the bottom22 of the bin 20 and secured to a stationary support frame 32 by similarbrackets 31a. Mounted on the support frame 32 is an eccentric 33 havingan eccentric rod 34 in the form of a leaf spring secured as by amounting bracket 34a to the bottom 22 of the bin 20. Also mounted on thesupport frame 32 is a gear box 35 and a prime mover 36 preferably of theelectric motor type. The eccentric 33 has a driven pulley. The gear box35 has both a drive pulley and a driven pulley. The prime mover 36 has adrive pulley. By means and a drive belt 38 between the drive pulley ofthe gear box 35 and the driven pulley of the eccentric 33 movement ofthe prime mover 36 is transmitted to the eccentric 33.

Under operative conditions the eccentric 33 imparts a motion to the bin20 which comprises vertical and horizontal components of motion with theresultant motion being in the direction of an inclined plane the lowerend of which is at the right-hand side of FIG. 3 and the upper end ofwhich is at the left-hand side of FIG. 3. The bin is supported asaforementioned upon the leaf springs 29 and .30 which allow for thisinclined motion. As the bin 20 moves upwardly along the incline, itserves to elevate and to move toward the lefthand end of the binarticles to be finished as well as finishing particles in the bin. Theincline is not a true incline but more of an arcuate incline. However,the vibratory movement of the bin imparted thereto by the eccentric 33is such that once the articles and particles are moving upwardly and tothe left as viewed ,suflicient to cause this continued motion thereofduring downward retraction of the bin. This completes one cycle ofvibratory movement. Successive cycles serve to continue the conveyingmotion of the articles and the particles in the bin toward the left-handend thereof. The leaf spring 34 serves to allow the vibratory movementof the supporting bed of the bin relative to the eccentric 33 whileconnecting the eccentric to the bin for the reciprocatory motion.

Such vibratory motion of the bin bottom 22 is rapid and the distance oftravel thereof is small. In this regard, it has been found that aneccentric speed of 800 revolutions per minute is satisfactory for thepurposes of this invention.

As shown in the figures of the drawings, the screen section 13 comprisesa generally horizontally disposed screen 40 mounted between the siderails of a generally horizontally disposed particle-receiving chute 41.The chute is mounted upon the support 32 similar to the mounting of thebin 20, i.e., upon a pair of leaf springs 41a and 41b as shown in FIG.4. A leaf'spring 410 connected to the chute and to an eccentric 41dserves to impart vibratory motion to the chute. The eccentric 4101 isdriven through a belt drive or the like 412 by an electric motor 41).Beneath the screen 40 the chute is provided with a bottom wall 46a uponwhich deburring particles rest upon falling through the screen. Thefinished articles remain on top of the screen 40. The vibratoryconveying motion of the chute conveys the articles and the particlestherealong from right to left as viewed in FIG. 4. The bottom wall 40aterminates as at 40b to define a particle-discharge opening 43 throughwhich finishing particles may discharge from the chute into an elevator14. The screen terminates at point 40c over the bottom wall of adischarge chute 42 leading to a storage space or collecting station.

The abrasive particle return section 14 comprises an elevator 44 forreceiving abrasive particles from the discharge opening 43 and forelevating the same to a height above the bin 26. Below the end of theelevator 44 at this height there is provided a downwardly inclinedparticle return chute 45, the bottom end of which is over the bin 20.The elevator 44 illustrated in FIGS. 1 and 2 of the drawings comprisesan endless belt 46 mounted at the upper end thereof on a drive roll 47and at the bottom end thereof on an idler roll 48. The outside of thebelt is provided with a plurality of flights 49 which intercept abrasiveparticles from the discharge opening 43, convey the particles upwardlyto the top end thereof and dump the same into the return chute 45.

Operation To prepare the machine 10 for use, the end closure member 26of the bin 29 is closed so that the bottom end thereof is in engagementwith the bottom 22 of the bin 20. Abrasive particles are introduced intothe bin 29 in suilicient quantity to provide a bed on the bottom 22. Thehopper 16 is then charged with articles to be finished. The machine It!is now ready for operation.

The vibratory conveyor 17 is then actuated whereupon articles to befinished are conveyed from the hopper discharge to the end of theconveyor 17 and into the bin 20.

The prime mover 36 is then turned on whereby vibratory conveying forcesare created by the vibratory conveyor assembly 21 and applied to the binbottom 22. This causes abrasive particles and articles to be finished tobe subjected to the vibratory conveying forces. Articles on top of thebed sink into the bed and become surrounded by the relatively abrasiveparticles.

Because of the difference in mass between the articles to be finishedand the relative abrasive particles, the vibratory conveying forcesacting thereon produce relative motion between the abrasive particlesand the articles to be finished whereby abrasive action on burrs orrough surfaces, or dirty surfaces to be cleaned on the articles takesplace and the surfaces are finished.

In addition, the particles and articles in the bed move towards the endclosure member 26. As particles and articles reach the end closuremember 26, they are deflected upwardly and backwardly because of thesemicircular shape of the end closure member 26. Such upward deflectioncauses a gentle circulatory movement of articles in the bed with theresult that all portions of articles to be finished are contacted by theabrasive particles regardless of the shape of the article.

When a desired number of articles to be finished have been introducedinto the bin 20 from the hopper 16, the vibrator conveyor 17 is thenstopped. After a sutficient period of time for finishing of all articlesin the bed has elapsed, the back end closure member 26 is opened byactuating the crank arm assembly 27 and the elevator 44 turned on.Because of the vibratory conveying action of the bottom 22 of the bin20, particles and articles are conveyed to the'back end thereof and ontothe screen 40. The motor 41 may be started simultaneously with theopening of the end of the bin 20, as well as the driving means (notshown) for the elevator 14. Abrasive particles and burrs fall throughthe screen 40 into the particle chute 41. Finished articles movedownwardly on the screen 40 and into the article-receiving chute 42whereby they are conveyed, for example, to an articlecollecting station.Abrasive particles on the particle chute 41 move to the dischargeopening 43 whereat they fall onto the top surface of the belt 46 of theelevator 44. Once on the endless belt 46 and with the aid of the flights49, the abrasive particles are elevated up to the upper end thereof anddumped into the return chute 45 and thereby into the bin 20.

When all of the finished articles have been discharged from the bin 20,the back end closure member 26 is closed as by actuating the crank armassembly 27. When the articles and particles have cleared the chute 40,motor 41] is de-energized, and the elevator 14 stopped once theparticles therein have been discharged back into bin 20. The startingand stopping of the various conveyors, the elevator, and the opening andclosing of end closure 27, may all be automatically controlled, ifdesired, in any suitable fashion. The procedure is then repeated.

The length of time which the articles to be deburred reside in the bin20 under normal operative conditions is dependent upon the nature of thesurface to be finished, the nature of the abrasive particles, thefrequency of vibration imposed upon the bin 20 and the amplitude of thevibration. These factors, obviously, are determined by local conditionsand can best be ascertained by the machine operator upon confronting thelocal conditions.

The number of articles to be finished in the bin 20 during eachfinishing cycle of the machine is dependent upon the volume of eacharticle, the volume of abrasive particles in the bed and the volume ofthe bed. These factors are again determined by local conditions. Ingeneral, optimum conditions are obtained when using abrasive particlesof smaller particle size than the articles to be deburred and when usinga dense bed of abrasive particles.

Thus there is provided a machine for finishing articles. Structure ofthe machine is readily comprehended and simple in nature. Moreover, itsoperation is quite simple and it does not require a highly skilledoperator.

A feature of advantage of this invention is that while the machine is inoperation, the operator can tell by visual inspection the extent offinishing which has occurred and when substantially all of the articleshave been surface finished.

Another feature of advantage of the machine is that the vibratoryconveyor action thereof can be controlled so that agitation and movementof the articles to be finished are gentle. Yet, because of the relativemotion between the abrasive particles and articles to be finished, theabrading, scrubbing, or deburring action is most effective.

Still another feature of advantage of this invention is that regardlessof the shapes of the articles to be finished, all surfaces of thearticles are contacted by the abrasive particles in following theteachings of this invention.

The method of this invention can be readily performed not only in thepreferred embodiment of the finishing machine illustrated in thedrawings, but in other machines of different construction.

The method of this invention is applicable not only with a bed ofabrasive particles in the dry state, but also to a bed of abrasiveparticles suspended in a liquid to form a slurry. Generally speaking,any of the conventional deburring or surface finishing solids such assand, siliconcarbides, and the like may be used in practicing theteachings of this invention.

I claim:

1. A method of surface finishing articles, which comprises: suspendingarticles to be finished in a bed of relatively abrasive particles havingan average mass different from the average mass of said articles;subjecting said bed to vibratory conveying forces directed toward oneend of the bed to establish relative motion between said articles andparticles and move both articles and particles generally toward said oneend; directing said articles and particles generally upwardly in acurvilinear path at said one end of the bed and thence downwardly awayfrom said one end completing a closed loop path; and continuing saidconveying forces to recirculate said articles and particles through thebed in said closed loop path.

2. A method of surface finishing articles, which comprises: suspendingarticles to be finished in a bed of relatively abrasive particles havingan average mass different from the average mass of said articles;subjecting said bed to vibratory conveying forces directed toward oneend of the bed to establish relative motion between said articles andparticles and move both articles and particles generally toward said oneend; directing said articles and particles generally upwardly in acurvilinear path at said one end of the bed and thence downwardly awayfrom said one end completing a closed loop path; continuing saidconveying forces to recirculate said articles and particles through thebed in said closed loop path; and thereafter utilizing said vibratoryconveying forces to vibratborily convey said articles and said particlesout of said References Cited by the Examiner UNITED STATES PATENTS2,554,022 5/51 Gould 51-163 2,660,835 12/53 Burden 517 2,664,676 1/54Cuppers 517 2,683,343 7/54 Gillette et a1. 513 15 2,720,730 10/55 Kroger51--7 2,748,549 6/56 Tuttle 51-316 3,108,408 10/63 Dalquist et al51--163 LESTER M. SWINGLE, Primary Examiner.

FRANK BJBAILEY, JOHN C. CHRISTIE, J. SPEN- CER OVERHOLSER, Examiners.

1. A METHOD OF SURFACE FINISHING ARTICLES, WHICH COMPRISES: SUSPENDINGARTICLES TO BE FINISHED IN A BED OF RELATIVELY ABRASIVE PARTICLES HAVINGAN AVERAGE MASS DIFFERENT FROM THE AVERAGE MASS OF SAID ARTICLES;SUBJECTING SAID BED TO VIBRATORY CONVEYING FORCES DIRECTED TOWARD ONEEND OF THE BED TO ESTABLISH RELATIVE MOTION BETWEEN SAID ARTICLES ANDPARTICLES AND MOVE BOTH ARTICLES AND PARTICLES